This application pertains to the art of particle comminuting and more particularly to one pass comminuting of centimeter sized pellets or particles to micron sized particulates. The invention is particularly applicable to comminuting vulcanized rubber and will be described with particular reference thereto. However, it is to be appreciated that the invention has other applications such as comminuting coal, thermoplastics, thermosetting plastics, woods, ceramics, glass, resins, and other materials.
To facilitate reprocessing of vulcanized rubber and other elastomeric materials for reuse, the materials are commonly reduced to micron sized particles. Heretofore, various methods and apparatus have been employed to reduce the elastomeric materials to micron size. However, the prior art apparatus have had certain drawbacks, particularly when used for commercial production. One method for producing small particulates has been to subject material to a cryogenic temperature. The embrittled material is ground by conventional grinding techniques. Commonly, the ground particles are large and must be refrozen and ground another time before they can be reused efficiently. Thus, this technique is expensive and finds great difficulty in producing particles in the lower micron range. Others have used abrasion devices for reducing the particle size of rubber and other elastomers. However, abrasion devices have relatively low particle yields. Further, abrasion devices have an inherent temperature increase that causes a hazard of the rubber combusting. Moveover, the elevated temperatures involved in prior art methods tend to degrade the material being processed.
Accordingly, it has been found desirable to provide an effective method and apparatus for comminuting of a vulcanized rubber and other elastomers to micron sized particles to facilitate reuse. The present invention provides an apparatus which although relatively simple in design and operation efficiently produces micron sized particles.